An application having common inventorship and filing date with this one, and entitled "Narrow Track Ferrite Head Cores", describes a magnetic head core for use in digital data recording on magnetic media. The outstanding feature of these cores are that the individual ferrite grains which have been sintered together to form a core have been cut along the edges which define the transducing face of the core, rather than having been torn from the surface by the machining process. As explained in the referenced application, the projection which carries the transducing face may be very thin (as thin as 0.025 mm.) and several times as tall as it is thick making in an extremely fragile element. To allow formation of such a projection by machining a brittle material such as ferrite, it is necessary to employ a grinding wheel having very low axial and radial runout. The subject of this invention is a grinding wheel which when precisely mounted on an air bearing spindle will have as good or better runout characteristics than that required by the referenced application. Of course, when the design of this grinding wheel mounting becomes well known, undoubtedly other applications for it will arise.